As the eye of Hurricane Sandy loomed a few hundred miles to the southeast and the monster storm churned toward the Mid-Atlantic coast, Marylanders braced for the arrival of a weather system with the potential to be the most damaging to hit the United States in 75 years.

Heavy rains and some gale-force winds hit the region Sunday evening, and still heavier rains and hurricane-force gusts were expected to strike late Monday and Monday night. Forecasters said the storm, currently rated as a Category 1 hurricane, would likely cause flash flooding, widespread power outages and treacherous road conditions.

As Sandy approached, the East Coast prepared for the worst. Schools and government offices told students and workers to stay home Monday. Hundreds of flights were canceled, while local transit systems shut down. Election officials closed early-voting polls on Monday. And the Maryland National Guard mobilized.

"This storm will be historic, destructive and life-threatening," said Bernie Rayno, a meteorologist with AccuWeather.com, adding that the collision of a cool, low-pressure system from the Midwest and a warm, high-pressure front moving up the coast have created unusually favorable conditions for a devastating storm.

As residents in Ocean City evacuated, people in the Baltimore region got their first taste of the conditions late Sunday and expected to see Sandy intensify by Monday morning and grow steadily worse throughout the day. As of Sunday night, 23 emergency shelters were preparing to open throughout the state.

Traffic on major arteries was light early Monday as motorists apparently heeded warnings to stay off roads as Hurricane Sandy slopped into the region.

Gusty rain fell in sheets on Maryland highways Monday morning, a prelude to the hurricane-force winds and downpour expected to hit later Monday and continue into Tuesday.

Baltimore Gas and Electric Co. mobilized more than 3,000 employees, contractors, out-of-state linemen and other personnel to prepare for extensive system damage and widespread outages in its central Maryland service area, according to Jeannette M. Mills, chief customer officer for BGE.

"We urge customers to prepare, and to review their emergency preparedness plan with their family, as we face the likelihood that Hurricane Sandy will result in extended, widespread power outages lasting several days," she said in a statement.

Forecasters were expecting the huge storm to make landfall sometime Monday, probably somewhere near Atlantic City on the New Jersey Coast. But the storm's breadth means that it's expected to engulf the entire East Coast. Meteorologists said it will be "life-threatening."

President Barack Obama declared a state of emergency in Maryland Sunday, ordering the Department of Homeland Security and the Federal Emergency Management Agency to offer federal aid in support of state and local responders.

"My message to the governors, as well as to the mayors, is anything they need, we will be there," the President said Sunday. "And we're not going to get bogged down with a lot of rules."

Baltimore Mayor Stephanie Rawlings-Blake said the city's emergency services were well-prepared for the storm — police and fire stations are fully staffed, she said, and both 911 and 311 are fully operational — but she urged residents to get ready for the hurricane before the gale-force winds hit.

"Prepare your property. Clear all storm drains. Check on your elderly relatives and neighbors and make sure that they are prepared," she said from the city's Emergency Operations Center, which went into operation early Sunday morning. "This is absolutely important."

Now is the time to get prescription drugs, she added, and to make sure the elderly do the same — and, if need be, go to the pharmacy for them before the rains get too heavy.

Baltimore City officials were not expecting to order evacuations, and they anticipated no disruption to Monday morning's commuter traffic, according to Ryan O'Doherty, a spokesman for the mayor's office. But the city was prepared to revise those predictions should conditions change overnight.

Baltimore also established shelters, opening at 9 a.m. Monday at the following locations:

As of Sunday, Amtrak and MARC trains were no longer running. The port of Baltimore also will be closed.

And more than 200 flights scheduled to land at or leave from Baltimore-Washington International Thurgood Marshall Airport Monday had already been canceled as of Sunday evening, according to FlightStats.com.

Jonathan Dean, a spokesman for the airport, said most carriers had indicated they would cancel all flights Monday and monitor the storm to make a decision about Tuesday and Wednesday. The airport will remain open, he said.

Public schools across the Baltimore region and most colleges in the area were to be shuttered Monday. Only essential workers were being asked to report to federal, state, city and some county offices.

The state park service closed down all parks and campgrounds through Wednesday morning.

Election officials announced they shut down early voting in Maryland as of Monday. The early-voting polls had been busy over the weekend in anticipation of the storm. Gov. Martin O'Malley will not make a decision about Tuesday's early voting until later Monday, a spokeswoman said. Early voting sites will be open at least one extra day, Friday, to make up for the cancellation.

Such precautions should come as no surprise, given the strange grandeur of a storm that some are saying could be the biggest to hit the U.S. since a massive hurricane known as the Long Island Express devastated large portions of the East Coast in 1938.

Hurricane Sandy would be less strong, meteorologists say, were it not for a rare confluence of patterns — the Midwestern trough colliding with the Atlantic front, which began as a tropical storm and is now transitioning to a chillier nor'easter status, all exacerbated by the tidal pull exerted by a full moon.

Conditions are so strange meteorologists aren't just calling for rain and high winds. They're predicting up to three feet of snow in the mountains of West Virginia, two feet in Tennessee and Kentucky and small amounts of snow in portions of western Maryland.

In Reisterstown, scores of emergency responders and state officials scrutinized weather maps, peered at live traffic cameras and drew plans to deploy crews and equipment at the state's emergency operations center Sunday.

"We're still preparing for the worst," said Edward J. McDonough, spokesman for the Maryland Emergency Management Agency. Although the eye of the storm was tracking north, state officials were preparing for extensive flooding — along coastal and tidewater areas as well as inland — and power outages, he said.

The Maryland National Guard was sending soldiers and equipment to counties throughout the region to be poised to help rescue people from swift water. About 4,500 soldiers were prepared to be called to help, said Lt. Col. Charles Kohler, a guard spokesman.

"We anticipate missions to assist in evacuations," Kohler said. Guard members in Humvees could ferry police and firefighters through water as deep as 30 inches, he said. By Sunday afternoon, Harford County officials had already requested the Guard's help with 12 different efforts, and Worcester and Queen Anne's County had also asked for significant assistance, he said.

Traffic appeared to be flowing smoothly out of Ocean City, where officials had ordered residents of some areas to evacuate.

Darrell B. Mobley, acting secretary of the Maryland Department of Transportation, watched live video of cars heading westward on Route 50. Although only one lane of Route 50 was open near Queenstown due to bridge construction, traffic was moving at a brisk speed.

Mobley urged motorists to avoid roadways during the storm's peak intensity, and to make plans to work from home Monday if possible.

In Annapolis, residents and visitors in town worked to tie down boats in marinas or secure them to docks.

Racing was canceled on Sunday in the Hillman Capital Management J/24 East Coast Championship, hosted this weekend by the Severn Sailing Association. Stan Havik, who usually keeps his 161/2-foot boat at the association's marina, was busy preparing it for a drive back to his home in Millersville.

"It seemed like the prudent course of action," he said. "With this sort of thing it's kind of hard to tell what's going to happen with the tide and the surge."

Rick Paullin, another boat owner who was taking his 18-foot boat back to his home in Davidsonville, said wind gusts like those expected can easily lift his 480-pound boat "like a toy and toss it." And in a city marina downtown, David Bond of Rhode Island was preparing for a rocky night aboard his 37-foot, all-wood 1965 Egg Harbor boat.

"I've got her all tied up, and I'm working on my rope line plan here, but there's only so much you can do," he said.

In the eastern Baltimore County communities of Bowleys Quarters and Carroll Island, residents were taking no chances as they weatherproofed homes and businesses.

The loud whir of a blower pierced the air as Bob Collins, who has lived on Beach Drive in Carroll Island for 16 years, cleared leaves from his gutters with the help of his girlfriend, Melissa Figinski of Columbia.

"I've tied everything down and pulled my boat from the water, so we're battening down the hatches," said Collins, who owns Accurate Termite-Pest Control Co. "But you're really powerless against the water."

Collins said his home was heavily damaged when Hurricane Isabel rumbled through the neighborhood in 2003.

"Everything on the first floor was ruined. I lost my workshop in the garage. My neighbor came on his Jet Ski into the living room and saved my daughter and then-wife," he said.

And in Fells Point, a neighborhood that often floods during weather events, a spirit of friendly preparedness manifested itself.

Steven Bond, a city Department of Transportation employee, said residents helped themselves to about 1,000 bags of sand an hour throughout Sunday at the foot of Broadway. A similar amount of bag-your-own sand was distributed at Thames and Caroline streets.

"It's flowing out of here. We have a good system going," he said.

Tanya Dunsey, who lives on Durham Street, said she was taking no chances after she saw a "torrential river of water" flow past her front door during other storms.

Others took the precautions in stride and seemed to be enjoying the assembly of people, which often included parents and their children.

"Look at the sense community here," said Jessica Gergen, who lives in Butchers Hill, as she surveyed the residents helping residents fill their bags with shovels and move the 45-pound plastic sacks to car trunks.

At Kooper's tavern on Thames Street, bar server Jessica Garonzik was even making a special drink, named a Dark and Stormy, a mixture of dark rum and ginger beer. At $5, the beverage has been a good seller throughout the weekend.

Elliott, the meteorologist, said there are still so many variables in play that it's hard to predict just where Hurricane Sandy will rank in the annals of American storms, though he was sure it would be in the conversation.

"People are going to be talking about this for decades," he said.

But at least one Baltimorean guessed the memories might not be all bad. Garrett Giusti, who owns a home on Fountain Street, said as scary as it is, the monster storm is already bringing positives to the fore.

"I prepare for the worst and hope for the best," Giusti said as he dumped a few sand bags in his trunk. "But look at the good spirit here. Everyone is helping out."